The reactions of dialkyl and diaryl disulfides with alkylating agents will be studied for the purpose of preparing alkylthiosulfonium salts (1) either as isolable compounds or as reactive intermediates. Alkylating agents to be used include electrophiles which are known to possess carcinogenic or antineoplastic activity. Alkylation with carbene electrophiles will also be attempted. Alternative routes to (1) will be tried, including the reactions of thioethers with sulfenyl compounds. The mechanisms by which alkylthiosulfonium salts rearrange and undergo nucleophilic displacement at carbon will be investigated using stereochemical and structural probes. The possible involvement of carbocations will be tested using salts which would undergo rearrangement in the alkyl group if they dissociate by way of carbocations. The propensity of alkylthiosulfonium salts to transfer an alkyl or an alkylthio group to nucleophiles will be explored using alcohols, thioethers, amines, ketones, and alkenes. The catalytic effect of tertiary amine bases in the solvolysis of sulfenyl compounds, and the possible involvement of alkylthioammonium salts will be studied.